I have been having trouble over import the mesh as it show these error and the object that shows in the importer is transparent.
Try scaling down the mesh in the program you made it?
I would try selecting the parts in blender that you want to import, then when it asks, say import selected. if that doesn’t work, I’d try importing half at a time
The limit is 10k tris. You need to simplify, or split up your mesh. What is it?
Your mesh is far above Roblox’s 10k tris limit. You’ll need to optimize it more.
Even if you reduce the mesh it is still transparent!
Maybe this post can help?